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Anders Irbäck. Photo.

Anders Irbäck

Professor

Anders Irbäck. Photo.

Dissecting the mechanical unfolding of ubiquitin

Author

  • Anders Irbäck
  • Simon Mitternacht
  • Sandipan Mohanty

Summary, in English

The unfolding behavior of ubiquitin under the influence of a stretching force recently was investigated experimentally by single-molecule constant-force methods. Many observed unfolding traces had a simple two-state character, whereas others showed clear evidence of intermediate states. Here, we use Monte Carlo simulations to investigate the force-induced unfolding of ubiquitin at the atomic level. In agreement with experimental data, we find that the unfolding process can occur either in a single step or through intermediate states. In addition to this randomness, we find that many quantities, such as the frequency of occurrence of intermediates, show a clear systematic dependence on the strength of the applied force. Despite this diversity, one common feature can be identified in the simulated unfolding events, which is the order in which the secondary-structure elements break. This order is the same in two and three-state events and at the different forces studied. The observed order remains to be verified experimentally but appears physically reasonable.

Department/s

  • Computational Biology and Biological Physics
  • Department of Astronomy and Theoretical Physics

Publishing year

2005

Language

English

Pages

13427-13432

Publication/Series

Proceedings of the National Academy of Sciences

Volume

102

Issue

38

Document type

Journal article

Publisher

National Acad Sciences

Topic

  • Biophysics

Keywords

  • Monte Carlo simulation
  • all-atom model
  • force-induced unfolding

Status

Published

ISBN/ISSN/Other

  • ISSN: 1091-6490